Quick-cook sulphite process



Patented Nov. 10, 1925.

UNITED STATES PATENT OFFICE.

PHILLIP C. ULMEN, OF RIVER ROUGE, AND HERMAN H. BECKER AND RUSSELL '1.MANN, OF DETROIT, MICHIGAN.

QUICK-COOK SULPHITE PROCESS.

Application filed April 14, 1924. Serial No. 706,542.

To all whom it may concern:

Be it known that we, PHILLIP C. ULMEN, a resident of River Rouge, countyof Wayne, and State of Michigan, and HERMAN H. BECKER and RUssELL T.MANN, residents of Detroit, county of \Vayne, and State of Michigan, allcitizens of the United States of America, have invented certain new anduseful Improvements in Quick-Cook Sulphite Processes, of which thefollowing is a full and clear specification.

- Our invention relates to the well-known quick-cook 'sulphite pulpprocesses, and the object is to so discharge the contents of thedigester as to preserve the strength of the fiber, as more fullyhereinafter set' forth.

The drawing is a diagram of a digester of ordinary construction equippedto carry out our invention.

In our preferred construction, we provide for a supply of cold water(preferably white water) under pressure through a supplypipe 1, which isconnected to a 'vertical branch 2 arranged alongside the digester. Thebranch-pipe 3 leads from the pipe 2 into the digester at the upper endthereof, this pipe being provided with a valve 4 and at its inner endwith a strainer 5.

Duplicate pipes 6 and 7 enter the lower part of the digester, the endswithin the digester being covered by strainers 8. The outer ends ofthese pipes empty into the usual large blow-off conduit 9 provided withthe usual blow-ofi valve 10. Each of opening the the pipes 6 and 7 isprovided with a pair of valves 11 and at a point between each pair ofvalves each pipe is connected by a branch 12 with the lower end of thepipe, 2, a valve 13 being provided in the pipe 2 at a point betweenbranch-pipes 12 and the main supply-pipe 1.

After the digesting process is completed and the digester is ready to bedischarged, we do not follow the usual practice of first contrary,proceed as follows: We first open the valves 11 and the valve 4, wherebythe spent liquor is discharged into the blow-off pipe 9 and thence tothe usual blow-pit, and

blow-off valve 10, but, on the at the same time a supply of fresh coldwater is admitted at the top of the digester. In this way, the pressureis quickly reduced, the temperature is likewise reduced and practicallyall the spent liquor is run off into the pit. We then close the twoouter valves 11 and leave one or both of the inner valves 11 open,preferably one; we likewise open valve 13;. then fresh cold water entersthe digester at the bottom through one or both of the strainers 8, whileat the same time the water continues to flow in through the strainer 5at the top; the main blow-off valve 10 is likewise opened. This resultsin the washing out of the cooked chips through the main blow-off valveinto the pit, as

usual.

Our process has the advantage that it avoids the bursting ofthe chipsthat results from, the present usual method of discharging quick-cookdigesters. This bursting of the chips results from thesudden release ofthe pressure through the usual blow-off valve. The steam, as is wellknown, cells of the wood suddenly expands, when thus released, with theresult that a considerable' portion of the chips is exploded and thefibers are destroyed or injured. With our method, the introduction ofthe cold water and simultaneous running off of the spent liquor quicklyreduces pressure and temperature without affecting the-original fullformof the chips, thus greatly increas- 1n of the fact that the chipsare discharged in practicall their original form, we subsequentlydisintegrate the chips by means 'ogfa suitable machine, which operationis a s mple and inexpensive one and is fully comin the the strength ofthe pulp fiber. In view pensated for by the increased strength of thepulp we get. Inpractice, we have succeeded in producing pulp whlch isnearly as strong as that obtaine by means of the longer. Mitscherlichmethod, and we have as possible and thus insure the cold water beingquickly distributed throughout the digester.

What we claim as newis:

The method of discharging quick-cook sulphite digesters consisting instraining oil? the spent liquor and simultaneously inject ing cold waterto thus quickly reduce the temperature and pressure within the digester,and then, after the temperature and .1

pressure have been thus reduced, washing out the cooked chips. Intestimony whereof we hereunto aflix our signatures this 31" day of March1924.

PHILLIP o. ULMEN. HERMAN H. BECKER. RUSSELL T. MANN.

